(10) Always bleach you browser cache / cookies / web logs! 35x gutmann style! (Bleachbit, Ccleaner, etc.)
(11) Browser Security: Use Noscript Security Suite add-on. Noscript is a must: make sure to block all global scripts, wipe the whitelist in Noscript and re-configure the whitelist that best fits your browser habits. IPFlood is also a useful add-on to obfuscate IP GET requests. You should use Random Agent Spoofer (or Blender) to spoof your browser & OS metadata while you surf the web, making it a lot more difficult to track your activity. Tin Foil is another great security addon. Also, make sure WebGL and WebRTC are disabled in about:config (research how to disable those, there are tutorials out there).
(12) Its best to have two computers, rather than just one. For example, have one just for banking / legit LEGAL purposes. Have another one (completely separated) just for private or illegal activity. Make sure you don't put any personal info in the private computer.
(13) Use encryption and strong passwords! Write them down on a piece of paper or memorize them. DO NOT store passwords on a computer file. That is a big no-no! Try easy to remember long sentences for passwords, and combine all the words together. The more characters used, the harder it is for hackers to break the passwords.
(14) Have separate email accounts for each kind of activity (legal or not, don't matter).
(15) Make sure you physically disconnect your web cam or cover it up with black electrical tape. Most laptops these days come with web cams attached above or below the monitor. Make sure the camera cannot be used to identify you or spy on you in any way. (Yes, webcams can be hacked / remotely hijacked to spy on you!)
(16) Avoid new "Smart TVs" (they spy on you too)! If you have a newer TV, make sure you cover up or unplug the camera and microphone. Or keep it offline and disconnected from the cable box when not in use. You could cancel cable and just rip DVDs of your favorite movies and shows instead, using them on an offline TV set.
(17) Avoid all new digitized vehicles. They can easily be hacked, used to spy on you and even be remotely hijacked by criminal entities/governments!
(18) Never allow another person to use your computer. Make sure you routinely backup important files to a flashdrive or DVD and store that data offline. Also make sure you have a backup copy of the OS you use as well as backups of the software you use. If you ever have problems with your OS someday, just wipe your partitioned OS, and then re-partition the OS again yourself from scratch. Do not allow others to 'fix' your computer, they could easily steal information from your OS you might not want them knowing about. Geek Squad works with the FBI and other agencies to steal data from their customers, do not trust them to fix or repair your computer.
(19) Any photos you take with modern cameras contain EXIF metadata that contain GPS coordinates among other data used to identify the owner of the photo. If you store your modern photos online, people will be able to identify you. Don't do it! I repeat: do not post modern photos online unless you want to be identified! (I have been told PNG formats do not store any metadata, so photos converted to PNG might be safe).
Test your online privacy and learn more: https://www.privacytools.io/